This invention relates generally to hopper tees, as used in bulk material handling, and more specifically pertains to a hopper tee which has an arcuate opening through its bottom, to facilitate unloading, but at the same time, incorporates an arcuate closure means that furnishes a cover for the opening and provides uniformity of even the interior dimensions for the formed tee, so as not to encumber the flow of granular material therethrough, when the tee is used for conveying such material to another location.
Hoppers, or tank trailers, regularly transport bulk commodities such as industrial and food products; and even such abrasive materials as sand, or other pelletized materials. When the hopper, or tank trailer, reaches its destination, the bulk commodity is unloaded, typically by a power takeoff driven from the truck mounted blower or a pneumatic system of a plant or factory. The bulk commodity generally unloads from the hopper, into a pipeline, for delivery. Or, the bulk material may pass from the hopper, directly into a tee, and the tee may incorporate an opened bottom, to allow the granular material to discharge directly therefrom. Usually, such hopper tees conventionally have a vertical section of constant dimension, and an integral shape of a horizontal section also of constant dimensions, for forming the inverted tee shaped configuration. To transfer the bulk commodity, the material moves out of the hopper, or bin, or out of the railroad car, by gravity flow or air pressure vibration induced flow, into the vertical section of the hopper tee. The discharge pipe is connected to the horizontal section of the tee. As noted, the prior art hopper tees usually have a complete, one piece assembly that includes a vertical section, including connecting to a hopper, and a horizontal section, connecting to a discharge pipe. The prior art hopper tee designs fit on the bottom of the bins of the pneumatic tank trailers, railroad cars, or the like. Typically, there may be a butterfly valve that connects on the flange of the hopper tee, to the bottom of the bin, which can be opened or closed during discharge. Although, prior art hopper tees function well for their intended purposes, some tees are structured where the granular material being unloaded will impinge upon specific surfaces of the tee, under pressure, or become embedded within parts of the tee itself, which has a tendency to cause abrasion, if not eventual wear through the tees at these active locations of the tee structure. Furthermore, where the butterfly valve is involved, there frequently is caused an impingement and embedding of the granular material within the structural components of the valve, the tee, the conveying line, and all of these can lead towards a contamination of subsequent loads, when another material is shipped by way of the bulk transfer vehicle.
Hoppers, or tank trailers, regularly transport bulk commodities such as industrial and food products. When the hopper, or tank trailer, reaches its destination, the bulk commodity is unloaded, typically by a power take off driven of the tank trailer mounted blower or a pneumatic system of a another source. The bulk commodity generally unloads from the hopper and into a pipeline. To complete the unloading, hopper tees are mounted to the discharge outlet of the hoppers, or bins. The hopper tee conventionally has a vertical section of constant dimension and shape of a similar horizontal section also of constant dimension and shape forming the inverted T shape configuration. To transfer the bulk commodity, the material is moved out of the hopper, or bin, by gravity flow or air pressure vibration into the vertical section of the hopper tee. The clean discharge pipe is connected to the horizontal section of the tee. Pneumatic conveyance of the bulk material through the pipe occurs by establishing a pressure differential in the pipe.
The prior art hopper tee designs fit on the bottom of the bins of pneumatic tank trailers. Typically, the valve of a bin bolts to the flange of the hopper tee. Although prior art hopper tees function well for their intended purposes, some hopper tees lack proper ground clearance for long trailers. Ground clearance has afflicted the tank trailer trucking industry for years. For example, as the hopper tee mounts under the tank, ground clearance problems arise when a long trailer, such as a tank trailer, crosses railroad tracks or other uneven surfaces. The longer the trailer, the easier a hopper tee becomes stuck upon a railroad rail, berm, or other short height surface condition. A stuck trailer delays delivery of product to its destination, risks delay penalties to the trucking company, and increases recovery and repair costs of the tank trailers.
The Department of Transportation (DOT) and state highway departments have established heights, widths and lengths the tank trailers must meet. When the hauler transports light density products, such as plastic pellets, the hauler requires a larger cubic foot capacity, or volume, to haul a maximum payload and make hauling such products economically feasible. To increase the cubic foot capacity and remain within DOT height, width and length standards, the prior art and industry have dropped the bottom of the hopper. However, the bottom of the hopper requires angled walls (due to the angle of repose of the bulk material) that funnel down to the hopper tee to allow for emptying of bulk granular material. For most dry bulk products the angle of repose is approximately 45 degrees to the horizontal to obtain the maximum tank volume, in cubic feet, while remaining within the mandated dimensions.